Releasable Water Charge-Trapping and Water-Resistant Photodetection using 1D Perovskitoid Hydrate Single Crystal

Hydrates of hybrid organic-inorganic perovskites have been discovered with MAPbI₃ and are proved to be unstable in atmosphere. However, the influence of water molecules on the performance of optoelectronic devices is still not fully understood. Here, using a dication, 2-(dimethylamino) ethylamine (DMEN²⁺ ), a stable quasi-1D perovskitoid hydrate single crystal is designed and successfully synthesized, which is formulated as DMENPb₂ I₆ ·H₂ O. In this design, both corner-sharing and edge-sharing connectivity are adopted, and water molecules are connected with the crystal through hydrogen bonding. It is discovered that such water sites distributed along the inorganic chains function both as charge traps and as releasable charge stocks. Optical excitation that overcomes the potential wells formed on these water sites may release these stocked charges and facilitate enhanced transportable charge density. Meanwhile, exciton diffusion and charge transport are strongly confined in the 1D transport channels. Above mechanisms are verified both by the transient absorption spectroscopy and by the photodetection performance. This introduces a new design strategy with a trapping-stock-releasing-transport roadmap for perovskitoid materials. Excellent water resistance endows this material with more advantages in the development of a new generation of optoelectronic devices.